Process of producing aluminum nitrid.



v treme ease.

OTTOKAR SERPEK, 0F PARIS, FRANCE, ASS IGNOR FFTCE.

T0 socrn'rn GENERALE nus NITRURES, 0F PARIS, FRANCE.

PROCESS OF PRODUCING ALUMINUM NITRID.

No Drawing.

Specification of Letters Patent. Application filed December 15, 1909.Serial No. 533,163.

Patented Mar. 21, 1911.

To all whom it may concern:

Be it known that I, OTTOKAR SERPEK, a subject of the Emperor ofAustria-Hungary, residing at 12 Rue ltoquepine, Paris, France, haveinvented certain new and. useful Improvements in Processes of ProducingAluminum Nitrid, of which the following is a specification.

This invention relates of aluminumnitrid by heating a mixture of carbonand alumina in the presence of nitrogen or in anatmosphere containingnitrogen.

More especially, my invention consists in observing and regulating thetemperature required for the said process in a distinct manner.

Numerous processes are already known for the combination of nitrogenwith metals. Various metal compounds have the property of uniting withnitrogen to form nitrids if they are heated to a very high temperaturein the presence of carbon. It has generally been supposed that thisprocess occurs through the preliminary reduction of the metal compound,for example, aluminum oxid to metal and the subsequent union of thiswith the nitrogen. It is undoubtedly the fact that many metals, as forexample magnesium combine with nitrogen with ex- It is therefore naturalthat most inventors should have thought that temperatures must beemployed which first cause the reduction of a metal compound to metal.Other proesses rest upon the fact that not the separation of the metalbut the formation of another metal compound, for."

example carbid, is first aimed at. -Upon this are based the knownprocesses which start from calcium carbid or calcium carbid formingmixtures.

The applicant has published and patented a series of processes, :thepurpose of which is the production of aluminum nitrid through theformation of aluminum carbid. As is well known aluminum nitrid is onlyformed at very high temperatures, preferably at the temperature of thearc furnace; The applicant has hitherto supposed that in processes forthe direct production of nitrid v the highest temperature obtainablewith the to the production.

mixture electric furnace should be employed. Very exact experiments inwhich the temperature has been determined by means of a iVanner opticalpyrometer have shown that the greatest formation of nitrid occurs atteinperatures'far beneath those hitherto considered necessary. Thesetemperatures are so low that the formation of aluminum carbid oraluminum in an atmosphere containing no nitrogen would be impossible.

If a mixture of aluminum or alumina compound and carbon is slowly heatedin a current of nitrogen, the thermometer being closely watched, anoticeable combination of nitrogen is found to occur at about 1100degrees. At 1500 degrees in about a quarter of an hour nitrogen isabsorbed up to 5 per cent. At 1700 degrees the combination appears tooccur much more energetically with distinct evolution of carbon monoxid,and at 1800 to 1850 degrees the reaction becomes even violent. Almostchemically pure lllll'l(l is formedwith an average nitrogen content ofabout 30 per cent. Alumina and *arbon may be mixed in molecularproportions, that is to say 102 parts by weight of alumina, with 36parts of carbon. Besides pure or impure alumina, such as naturalbauxite, aluminum borates or silicates may 'be used for carrying 'outthe process. The reaction is quite distinctfrom that which occursbetween chalk and carbon under cumstances. Calcium carbid forming mixt-ures only take up about 5 per cent. nitrogen at 1800 degrees.

I claim 1.,The process of producing aluminum nitrid which processconsists in heating a mixture consisting of aluminous compounds andcarbon in anatmosphere containing nitrogen at temperatures not exceeding2000 centigrade.

2. The process of producing aluminum nitrid WhlCh process consists inheating a mixture consisting of alumina and carbon in an atmospherecontaining nitrogen at tour peraturesnot exceeding- 2000 centigrade.

3. The process of producing aluminum nitri d which process consists inheating a consisting of aluminous compounds and carbon in an" atmospherecontaining nitrogen at a temperature of about 1800" i In. testimonywhereof 1 have signed my centigrade; 1 name to this specification in thepresence of 4. The process of producing aluminum two subscribingwitnesses.

n'itrid which process consists in heating a 't OTTOKAR SERPEK.

" 5 inixture consisting of alumina'and carbon \Vitnesscs:

in an atmosphere containing nitrogen at a GEORGE Girrono, temperatureofabout 1800 Centigrade. ARNOLD ZUBER.

Copies of this patent niay be obtained for five cents each, byaddressing the Commissioner of Patents, Washington, D. 0.

